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Terms for Device Ontology

Introduction

This list of device-related definitions supports the Device Ontology Working Group of the Marine Metadata Interoperability project.

The first set of definitions are terms used directly in the ontology, and will be incorporated into the ontology in due course.

The second set of definitions are useful in discussing ontology concepts, but have not been incorporated into the ontology.

Many of the definitions are derived from SWE and similar standards, though most are reframed for this activity.

Synonyms are separated by semi-colons (;).

Terms

Device Ontology Terms

The device ontology contains the following terms.

deployment

association of an entity to another entity (as for example, a device to a physical system that incorporates it, to an observation campaign, or to a location), for a determinable period of time

device

physical entity that performs a task and produces one or more outputs; it may contain other devices

deviceName; longName

a descriptive name which nominally identifies a specific device (type or instance) is meant (should be unique if an instance, but often is not)

feature; feature of interest; measurable particular

an abstraction of real-world phenomena [ISO 19101]; the generic carrier of properties [SWE O&M], a medium and extent in which a property exists; an identifiable object that can be observed; a feature of any type (ISO 19109, ISO 19101), which is a representation of the observation target, being the real-world object regarding which the observation is made.Examples: water; air; hydrosphere; Pacific Ocean..

manufacturerName, creator

the (name of the) organization that creates a device

modelNumber

a string assigned by a device manufacturer to signify a particular type of device

observingSystem

a type of system that is configured to make multiple observations over a period of time; typically makes many different kinds of observations within the same broad physical space

platform; basePlatform

physical entity upon which a component (such as a system) can be physically deployed; in this ontology, a platform only has mechanical attributes, not power, processing, or communication attributes

process

method, algorithm or instrument, or system of these; see also 'procedure'

processInput

any information that is provided to a process for its use

processOutput

any information that is reported from a process (may or may not have been generated by the process)

sampler

a component that obtains a physical piece or subset of an observed feature

sensor

a component that detects (measures) a physical phenomenon, converting it into a digital representation that can be output to other components

serialNumber

a string assigned by the device manufacturer to uniquely identify the device instance, in combination with the manufacturerName and (often) the modelNumber

system

a collection of components that work together toward a common objective

transducer

a device that converts an input signal into an output signal of a different form

The following are some ontology terms that we are using for the development of our device ontology. These terms are introduced in a rather informal manner. For more formal material, see for example the OWL Guide and references therein.

datatype

Any of the sets of elements denoted by RDF literals and XML Schema datatypes. Datatypes include numbers, strings, dates, and booleans. We sometimes refer to these as sets of atomic or simple elements.

class

A class is a set of elements (individuals) which are complex in contrast to datatypes. Note that, strictly speaking, a datatype is also a class (for example, 21 and -3011 are elements of the set of numbers). However, OWL distinguishes sets of simple elements (ie., datatypes) and sets of other complex elements (classes). Examples: Person (the set of all persons); System (the set of all physical systems in our device ontology).

property

A property is a binary relation, ie., it relates elements in a domain set with elements in a range set. Two types of properties are distinguished: datatype properties (where the range is a datatype), and object properties (where the range is a class). In both cases the domain is a class.

symmetric property

A property P is symmetric if, from the fact that x is related with y by P, then we can infer that y is related with x by P. Example: isMarriedWith (which can be specified over domain Person and range Person).

transitive property

A property P is transitive if, from the fact that x is related with y by P, and the fact that y is related with z by P, then we can infer that x is related with z by P. Example: isTallerThan (which can be specified over domain Person and range Person).

functional property

A property P is functional if an element on the corresponding domain class can have only one element associated in the range set. Examples: hasAge (domain: Person, range: number); hasSerialNumber (domain: System, range: string).

inverse functional property

A property P is inverse functional if its inverse is functional. Quoted from the OWL Guide, "Think of the elements of the range in an inverse functional property as defining a unique key in the database sense. [...] the elements of the range provide a unique identifier for each element of the domain."

Other Useful Terms

dimension

any directly measurable physical quantity such as mass (M), length (L), and time (T), and the derived units obtainable by multiplication or division from such quantities (library.thinkquest.org); a set of equivalent units of measure, where equivalence between two units of measure is determined by the existence of a quantity preserving one-to-one correspondence between values measured in one unit of measure and values measured in the other unit of measure (Wikipedia)

determinand; property type

parameter or a characteristic of a phenomenon subject to observation

observedProperty

the phenomenon for which the observation result provides an estimate of its value. It must be a property associated with the type of the feature of interest.(Note: The potential domain for measurable property and observedProperty is the same, but the former includes all measurable properties intrinsic to the real-world object, whereas the latter only includes properties that have actually been measured.)

observation

an act of observing a property or phenomenon, with the goal of producing an estimate of the value of the property. A specialized event whose result is a data value; an act associated with a discrete time instant or period through which a number, term or other symbol is assigned to a phenomenon

measurand; measurable property

physical parameter or a characteristic of a phenomenon subject to a measurement, whose value is described using a Measure (ISO 19103). Specialization of observable property-type.Examples: temperature, length, salinity

measurement; observation result

value(s) obtained by observing a property or phenomenon

phenomenon; property-type

concept that is a characteristic of one or more feature types, the value for which may be estimated by application of some procedure in an observation; a property of a feature of interest.Examples: wave height, organism size, ocean current direction

procedure

a description of the Process used to obtain the result; often an instrument or sensor, but may be a human observer, a simulator, or a process or algorithm applied to more primitive results used as inputs.

Resources

OGC-07-022r1 Observations and Measurements Part 1 (excerpt)

An Observation is an action with a result which has a value describing some phenomenon. The observation is modelled as a Feature within the context of the General Feature Model [ISO 19101, ISO 19109]. An observation feature binds a result to a feature of interest, upon which the observation was made. The observed property is a property of the feature of interest. An observation uses a procedure to determine the value of the result, which may involve a sensor or observer, analytical procedure, simulation or other numerical process. The observation pattern and feature is primarily useful for capturing metadata associated with the estimation of feature properties, which is important particularly when error in this estimate is of interest.

An observation results in an estimate of the value of a property of the feature of interest. Observation values may have many datatypes, including primitive types like category or measure, but also more complex types such as time, location and geometry. Complex results are obtained when the observed property requires multiple components for its encoding. Furthermore, if the property varies on the feature of interest, then the result is a coverage, whose domain is the feature. In a physical realisation, the result will typically be sampled on the domain, and hence represented as a discrete coverage.

SensorML provides a standard means by which sensor and platform capabilities and properties can be published and discovered. (p. 27)

From Section 7.4 "Relationship of the sensor to a platform:"

Within SensorML, platforms and sensors are treated as separate entities. Typically a sensor will be modeled as consisting of one or more detectors, whereas a platform will be modeled as a System that contains all of the sensors and defines positional and temporal relationships among them. (p. 33)

The main importance of the associated platform(s) is in providing the relationship of the sensor and its observations to some relevant external coordinate system (for example, a geospatial reference system). (p. 34)

... one can also choose to simply relate sensor locations relative to other sensors that are responsible for providing location (e.g., a GPS sensor) and attitude (e.g., an inertial navigation system). (p. 35)

From the Terms and definitions:

4.9 Measurand

Physical parameter or a characteristic of a phenomenon subject to a measurement, whose value is described using a Measure (ISO 19103). Subset of determinand or observable. [O&M]

4.10 Measure (noun)

Value described using a numeric amount with a scale or using a scalar reference system [ISO/TS 19103]. When used as a noun, measure is a synonym for physical quantity.

4.11 Measurement (noun)

An observation whose result is a measure [O&M]

4.13 Observable, Observable Property (noun)

A parameter or a characteristic of a phenomenon subject to observation. Synonym for determinand. [O&M]

4.14 Observation (noun)

An act of observing a property or phenomenon, with the goal of producing an estimate of the value of the property. A specialized event whose result is a data value. [O&M]

4.15 Observed Value

A value describing a natural phenomenon, which may use one of a variety of scales including nominal, ordinal, ratio and interval. The term is used regardless of whether the value is due to an instrumental observation, a subjective assignment or some other method of estimation or assignment. [O&M]

4.17 Phenomenon

A physical property that can be observed and measured, such as temperature, gravity, chemical concentration, orientation, number-of-individuals

(Sensor) Platform

An entity to which can be attached sensors or other platforms. A platform has an associated local coordinate frame that can be referenced to an external coordinate reference frame and to which the frames of attached sensors and platforms can be referenced.

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